Critical Analysis of Nonwoven Fabric Manufacturing Technologies

“Nonwoven Technologies: A critical analysis 2013
Vignesh Dhanabalan and Daniel Karthik 1
“Nonwoven Technologies: A critical analysis”
Authors: Vignesh Dhanabalan and Daniel Karthik.
Email: vigneshdhanabalan@hotmail.com
Abstract
Nonwoven fabrics have quietly revolutionized consumer, medical, and industrial market places
throughout the world. They have been the ingredient through which many traditional products
have been made better and the means by which many new products have been made possible.
Nonwovens are the fabrics that you don’t see, but are there where you need them; they are the
fabrics that you don’t recognize, but are performing in ways that others can’t.
In this paper an overview regarding the manufacturing of Non-woven have been
elaborately emphasizing on fiber usage, various web laying technology, conversion of webs into
fabrics along with the fabrics characteristics, market application and conclusion on the market
usage.
Keywords: Bonding technique, fiber interlocking laminate nonwoven, sanitary products, tissue,
use and throw materials
1. Introduction:
Nonwoven is an engineered fabric structure made directly from fibers, to provide specific
function to ensure fitness for purpose. The term “nonwoven” is often used as a generic
description of a fabric that is not produced by process of weaving or knitting, more broadly, a
fabric that is different from a traditional textile fabric. Like textile fabrics, nonwoven is a planar
structure that is produced with varying degrees of integrity, surface texture, thickness, flexibility,
and porosity that involves low cost and production process. In fact, the technologies used to
make nonwoven fabrics are based on fundamental principles used to produce textiles, papers,

and plastics. In this regard, nonwovens are fabrics that are made by mechanically, chemically, or
thermally interlocking layers or networks of fibers or filaments or yarns.
In spite of this mass-production approach, the nonwovens industry produces wide range
of fabric properties from open wadding suitable for insulation containing only 2–3% fibers by
volume to stiff reinforcing fabrics where the fiber content may be over 80% by volume. One of
the major advantages of nonwoven manufacturing is that, it is generally done in one continuous
process directly from the raw material to the finished fabric. When compared to other fabric
manufacturing techniques non woven technique is found to the best in terms of production ratio.
The production ratio of various techniques are tabulated below
2. Raw materials and their properties
The end use of materials has been the driving force for the development of products and
technology. Raw material is the key factor in designing of material, the selection of raw material
affects the function and quality of the product.
Technology Machine Production Ratio
Weaving
Automatic with shuttle
Automatic without shuttle
1
2
Knitting
Circular knotting
Warp knitting
4
16
Nonwoven
Dry method
Stitch bonding
Fine fiber carder
Coarse fiber carder
Tufting machine
Aerodynamic web making machine
Spin bonding machine
38
120
400
500
600
200-2000
Wet method Rotoformer
Paper making
2300
40000-100000

Fiber as raw material with their advantages and disadvantages are tabulated in Table.1

General production steps for non woven manufacturing

The manufacturing processes for nonwoven fabrics invariably consist of two distinct phases, web
formation and followed by subsequent bonding
3. Web forming Techniques
Web Formation
3.1 Dry laid process:
In dry laid process, web is produced from staple fibers. These fibers are directly laid from
a carding machine to form the matt ranging from 10-2500 gsm. The carding machine used is not
the regular ones they are equipped with worker and stripper rollers. There are three methods for
dry lying of web.
3.1.1 Parallel lying:
The mass per unit area of card web is normally too low to be used directly in a
nonwoven. They are increased by laying several card webs one over the other to form the matt.
The simplest and cheapest way of doing this is by parallel lying. Figure 1 show five cards raised
slightly above the floor to allow a long conveyor lattice to pass underneath. The webs from each
card fall onto the lattice forming a matt with five times the mass per unit area.
Web
formation
Drylaid
Parallel laid
Cross laid
Air laid
Wet laid Polymer laid
Spun bond
Melt blown

Fig 1: parallel laying of carded webs
3.1.2 Cross lying:
In cross lying, the cards (or cards) are placed at right angles to the main conveyor as
shown in Fig.2. In this case the card web is traversed backwards and forwards across the main
conveyor resulting is a zig-zag motion as shown in Fig 2
Fig 2: Cross laying of card web
3.1.3 Air lying:
The air-laying method produces the final matt in one stage without first making the
intermediate lighter weight web. It is capable of running at high production speeds but is similar
to the parallel-lay method. The width of the final matt is the same as the width of the air-laying
machine, usually in the range of 3–4m.
Opened fiber from the opening/blending section is fed into the back of hopper (A), which
delivers a uniform sheet of fibers to the feed rollers. The fiber is then taken by the toothed roller
(B), which is revolving at high speed. The worker and stripper rollers set to the roller (B) to
improve the opening power. A strong air stream (C) dislodges the fibers from the surface of
roller B and carries them onto the permeable conveyor on which the matt is formed. The

stripping rail E prevents fiber from reticulating round the cylinder B. The air flow at D helps the
fiber to stabilize in the formation zone.
Fig 3: Air laying technique
3.2 Wet lying
The wet-laid process was mainly developed from papermaking. This was undertaken
because the production speeds of papermaking are very high compared with textile production.
Textile fibers are cut very short by textile standards (6–20mm), but at the same time these are
very long in comparison with wood pulp. The fibers are then dispersed into water and the rate of
dilution has to be great enough to prevent the fibers aggregating.
Wet-laid nonwovens represent about 10% of the total market, but this percentage is
tending to decline. They are used widely in disposable products, for example in hospitals as
drapes, gowns, sometimes as sheets, as one-use filters, and as cover stock in disposable nappies
etc.
Fig 4: manufacturing of spun laced fabric

3.3 Polymer lay
3.3.1 Spun lying
Spun lying includes extrusion of the filaments from the polymer raw material, drawing
the filaments and laying them into a matt. As laying and bonding are normally continuous, this
process represents the shortest possible textile route from polymer to fabric in one stage. When
first introduced only large, very expensive machines with large production capabilities were
available, but later much smaller and relatively inexpensive machines have been developed.
Further developments have made it possible to produce microfibers on spun-laid machines
giving better filament distribution. Smaller pores present between the fibers for better filtration,
softer feel and also the possibility of making lighter-weight fabrics. For these reasons spun-laid
production are increasing more rapidly than any other nonwoven process.
Fig 5: spun lying technique
Melt blown
Melt blowing is another method of producing very fine fibers at high production rates
without the use of fine spinnerets. Figure 6 shows that the polymer is melted and extruded in the
normal way but through relatively large holes. As the polymer leaves the extrusion holes it is hit
by a high speed stream of hot air at or above its melting point, which breaks up the flow and
stretches the many filaments until they are very fine. At a later stage, cold air mixes with the hot
and the polymer solidifies. Then the jet of fiber are collected on the collector in the foam of
membranes.

Fig 6: Melt blown technology
4. Bonding Techniques
Bonding is the sequential process in manufacturing of nonwoven product. The web that is
formed in the above mentioned process is not sufficient enough to hold them together they have
to bonded to ensure no loss of material is found during usage.
4.1.1 Needle punching technology
The needle punching system is used to bond dry laid and spun laid webs. The needle
punched fabrics are produced when barbed needles are pushed through the fibrous web, forcing
fibers to form self interlock. This action occurs in needle punching around 2000 times a minute.
• Needling Technology
• Stitch Bonding
• Hydro-Entanglement
Mechanical
bonding
• Saturation bonding
• Foam bonding
• Spray bonding
• Print bonding
• Powder bonding
Chemical
bonding
• Hot Calendaring
• Belt Calendaring
• Through Air Bonding
• Radiant bonding
• Ultra-sonic bonding
Thermal
bonding4.1 4.2 4.3

Fig 7: working of needle punched fabric
In needle punching the bonding of the fiber web is the result of intertwining of the fibers
and of the inter fiber friction caused by the compression of the web.
Product characteristics
Needle felts have a high breaking tenacity and also high tear strength but the modulus is
low and the recovery from extension is also poor. Their Unique physical properties like
elongation in all (x, y,& z) directions for mould able applications is good. High strength makes
them an overwhelming choice of geo-textiles. The principal advantage is that the nonwoven is
practically homogeneous in comparison with a woven fabric so that the whole area of a
nonwoven filter can be used for filtration, whereas in a woven fabric the yarns effectively stop
the flow, leaving only the spaces between the yarns for filtration.
Applications of a needle punched nonwovens
Geotextiles Automotive
fabrics
Hometech Sportech Furniture Other
technical felts
Road and railway
construction,
dams, roofing and
drain felts, shore
protection,
Head liners,
door trim,
parcel shelves,
carpets, ,
insulation felts,
gas filters
Carpets,
wall
coverings,
decor felts,
wipe
blankets...
Shoe,
bags,
sport
goods
Shoulder
pads,
waddings,
mattresses
polishing
felts, abrasive
felts, mineral
fiber felts for
insulation

4.1.2 Hydro entanglement/Spun lace technology
The process of producing an entanglement by means of heavy water jets at very high
pressures through jet orifices with very small diameters is spun lace technique. This is similar to
a needle loom, but uses lighter weight matt. A very fine jet of this sort is liable to break up into
droplets, particularly if there is any turbulence in the water passing through the orifice. If
droplets are formed the energy in the jet will spread over a much larger area of matt so that, the
energy per unit area will be much less. Consequently the design of the jet to avoid turbulence and
to produce a needle-like stream of water is critical.
Fig 8: Hydro entanglement technique
Products made from spun lace technique have very good textile drape (low stiffness) and
very soft to handle. No chemical or melt binder is required therby making its product possible to
prepare 100 % natural fibers suitable for sanitary products.
uniform surface can be obtained due to more fine interlacing of fibers (compared to
needling). Very high textile production: up to 300 m/min for carded airlaid webs and of up to
500 m/min for wetlaid and spunbond (meltblown) can be made. Faric width up to 6000 mm can
be produced. So wide range of textile structure (depending especially on the perforated belt
structure) can be designed and manufactured.

Spunlace applications:
Hospital Medical Sanitary
products
Household
products
Industrial
textiles
Automotive
products
Other
applications
surgical
gowns and
drapes,
operational
cover
sheets, bed
sheets,
towels
wound
dressings,
gauze, wet
tissue, cotton
products,
pads.
baby
wipes,
facial clean
wipe, face
masks,
disposable
pants.
cleaning wipes,
protection
fabric for
electronics,
home furnishing
fabrics, table
cloths and
napkins,
curtains.
industrial
wipes,
filtration,
roofing, water
insulation,
protective
apparell,
liquid
absorbents
headliners,
cleaning
wipes
Interlinings
Coating
substrates for
synthetic
leather.
Stitch bonding technique
It is a technique in which fibers in a web are bonded together by stitches sewn or knitted
through the web to form a fabric. The finished fabric usually resembles corduroy.The fibers are
bonded into the loops but the thread does not contribute to loop formation. The basic types of
structure are pillar-stitch and tricot-stitch (Fig.9). It is also possible to use two systems of
threads, so both the types of structure can be simultaneously applied.
Fig 9: Formation of stitch bonding

They are highly voluminosity, softness and have good absorbent behavior, good elasticity and
air-permeability. Finishing the raw web-knitted material by means of raising, cropping or
tumbling, an even raised pile is achievable in heights ranging from 2 to 17 mm. Such pile web-
knitted fabrics with base material are suitable for the manufacture of blankets, shoe lining, soft
toy material and lining for winter garments.
Applications of stitch bonded fabrics:
Automotives Upholstery Sport tech Apparel Others application
surface covers
for various
molded
components,
parcel shelves
and head liners
covering material for
mattresses and beds,
decorative fabric,
base material are
suitable for the
manufacture of
blankets
Fabric in
training
shoes, shoe
lining
Lining for
winter
garments.
For insulation, soft
toy material,
filtration materials
as well as packing
materials.
Adhesive/Chemical Bonding
Chemical bonding involves treating either the complete matt or alternatively isolated
portions of the matt with a bonding agent with the intention of producing cohesion between fiber
layers. Although many different bonding agents could be used, the modern industry uses only
synthetic lattices, of which acrylic latex represents at least half, and styrene–butadiene latex and
vinyl acetate latex roughly a quarter each. When the bonding agent is applied it is essential that it
wets the fibers, otherwise poor adhesion might result. Most lattices inherently contain a
surfactant to disperse the polymer particles, but in some cases additional surfactant may be
needed to aid wetting. Followed by drying of latex by evaporating the aqueous component and
leaving the polymer particles together with the additives. During this stage the surface tension of
the water pulls the binder particles together forming a film over the fibers and a rather thicker
film over the fiber intersections. Smaller binder particles will form more effective film than

larger particles, other things being equal. The final stage is curing and in this phase the matt is
brought up to a higher temperature than drying for the fixation to take place.
There are different ways to carry out the chemical bonding process. Some of the commonly used
ones are:
 Saturation bonding: saturation bonding wets the whole matt with bonding agents, so that
all fibers are covered in a film of binder.
 Foam bonding: Application of chemicals as foam. The binder solution and measured
volume of air are passed continuously through a driven turbine which beats the two
components into consistent foam.
 Spray bonding: Similar latex binders may also be applied by spraying, using spray guns
similar to those used in painting, which may be either operated by compressed air or be
airless.
 Print bonding: Print bonding involves applying the some types of binder to the matt but
the application is to limited areas and sets a pattern
 Powder bonding: the bonding agent in the powder form is sprinkled.
The fabric property is governed by the elastic nature of the fiber and the resin. Hence the
fabric modulus is of the order of the fiber modulus that is extremely high. A high modulus in a
spatially uniform material means that it will be stiff, which explains why saturation-bonded
fabrics are very stiff relative to conventional textiles. At the same time tensile strength is low,
because the bonds tend to break before most fibers break.
Print-bonded fabrics are much softer in feel and also much more flexible owing to strong
effect of the free fibers in the unbounded areas. They are also significantly weaker than
saturation-bonded fabrics owing to the fibers slipping in unbounded areas, but knowing the fiber
length and the fiber orientation distribution it is possible to design a print pattern which will
minimize the strength loss.
Each spray application alters the thickness of the matt slightly, but it is still left
substantially lofty, the drying and curing stage also causes some small dimensional changes. The

final product is a thick, open and lofty fabric used widely as the filling in quilted fabrics, for
duvets, for some upholstery and also for some types of filter media.
Applications of chemical bonded fabrics:
Apparel purpose Sanitary purpose Home tech
Interlining fabric for textile
clothing, disposable/protective
clothing.
Some types of filter fabric, in
some cover stock and in
wiping cloths.
filling in quilted fabrics, for
duvets, for some upholstery
4.3 Thermal bonding
Thermal bonding is increasingly used at the expense of chemical bonding for a number of
reasons. Thermal bonding can run at high speed, whereas the speed production of chemical
bonding is limited by the drying and curing stage. Thermal bonding takes up little space
compared with drying and curing ovens. Also thermal bonding requires less heat compared with
the heat required to evaporate water from thebinder, so it is more energy efficient.
Thermal bonding requires a thermoplastic component to be present in the form of a
homophile fiber, powder, film, web, hot melt ores a sheath as part of a bicomponent fiber. Heat
is applied until the thermoplastic component becomes viscous or melts. The polymer flows by
surface tension and capillary action takes place at fiber-to fiber crossover points where bonding
regions are formed.
Fig 10: Thermal bonding technique

Methods of thermal bonding
 Hot calendaring
 Belt calendaring
 Through-air thermal bonding
 Ultrasonic bonding
 Radiant-heat bonding, etc.
Product characteristics:
Products can be relatively soft and textile-like depending on blend composition and bond
area. The material production does not involve any chemical use making it environmentally
friendly and 100 % recycling of fiber components can be achieved. High bulk products can be
bonded uniformly throughout the web cross section
Applications:
Designing Upholstery Food processing Medical textile
Composites and
Laminates
Interlinings,
Carpet backings
Food coverings,
Tea bags
Cover stock for
sanitary products,
Wiping cloths.
Finishing
Non woven are considered finished products when they are out of the production line no
external chemical or mechanical finishing is required t maintain its property. Special treatments
like flame retardant, antistatic agents, antimicrobial, coloration might be applied to increase their
functional property.
General overview
Needle felts have a high breaking tenacity and also high tear strength but the modulus is
low and the recovery from extension is also poor. For this reasons, needle felts subjected to load
has to have some form of reinforcement to control the extension to give better dimensional
stability and increases the resistance to wear.
The wipes produced by hydro entanglement are guaranteed lint free, because it is argued
that if a fiber is loose it will be washed away by the jetting process. It is interesting to note that

the hydro entanglement process came into being as a process for entangling matts too light for a
needle loom, but that the most recent developments are to use higher water pressures (400 bar)
and to process heavier fabrics at the lower end of the needle loom range. Fabric uses include
wipes, surgeon’s gowns, disposable protective clothing and backing fabrics for coating.
Thermal bonding is much less energy intensive, kinder to the environment and more
economical. The bonding method has a significant effect on product properties. Depending on
the bonding method, product properties vary from nonporous, thin, and non extensible, and
nonabsorbent to open, bulk, extensible and absorbent. All thermal bonding methods provide
strong bond points that are resistant to hostile environment and to many solvents too.
Bond strength increases up to a maximum and then decreases with increase in bonding
temperature for both staple fiber thermal bonding webs. Bond strength increases with increase in
bond area. Bond strength increases with increase in bond size. Effect of bonding temperature,
bond area, and bond size on fiber morphology in the unbonded region is negligible.
Conclusion
Nonwoven fabrics have quietly revolutionized consumer, medical, and industrial Market
places throughout the world. They have been the ingredient through which many traditional
products have been made better and the means by which many new products have been made
possible.
Nonwovens are the fabrics that we don’t see, but are there where we need them; they are
the fabrics that we don’t recognize, but are performing in ways that others can’t. Each of the
basic technology systems has its specific advantages and limitation. Researches and experimental
works are being carried out to explore the best possible use of nonwoven.
Although the world market of nonwoven products continuously grows, it faces the
structural readjustment followed by the change of global economic condition, raw material
capacity and consumers’ needs and behavior. In addition, new expansionary manufacturers are
emerging while the existing nonwoven producers are concerned by present consumers.

References
1. Dipl.ing, radko karcma, Manual of non-woven, Textile trade press, W.R.C smith
publication, Atlanta, USA, 1971.
2. Gulrajani, papers of international conference on Nonwovens, The textile institute north
India section, 5th
dec 1992.
3. Dharmadikary.R.K, Gilmore.T.S, thermal bonding f nonwoven, Textile progress vol (26),
n.o2, (ISBN 00405167), 1995.
4. Russel.S.J, Hand book of nonwovens, CRC press, Wood head publications, 2007.
5. Laga.S.K, Wasif.A.I, Nonwoven development and prospect, (unpublished document).
6. Hoon Joo Lee, Nancy Cassill, Analysis of World Nonwovens Market, College of Textiles,
North Carolina State University, 2401 Research Dr. Raleigh, NC 27695.
7. E.A. Vaughn, Nonwoven Manufacturing Technology Overview, School of Materials
Science and Engineering, Clemson University.
8. Milin patel & Dhruvkumar dhrambutt, Non woven technology, M S university- vadodara
9. Rupali Chitnis, Nonwovens In Meditech- Process & Technology, A.T.E, Mumbai
10. Mr. P.K.Roy, Mr.Tanveer Malik and Mr.T.K.Sinha, Thermal bonded nonwoven – an
overview.

Vignesh Dhanabalan
(M.Tech Technical Textiles)
Lecturer (Textile Technology)
SGGS College of Engineering and Technology,
Vishnupuri, Nanded,
Maharashtra, INDIA
vigneshdhanabalan@hotmail.com
+919790346612 / +918378836766

Critical Analysis of Nonwoven Fabric Manufacturing Technologies

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